Platen removing facility



Jan. 3, 1956 w. c. JONES PLATEN REMOVING FACILITY Filed Dec. 26, 1952 NVENTOR. W/LLARD C JONES Wfwf/ ATTORNEY y l 2,129,323 v PLATENREMovINo FACILITY v Application December 26, 1952, Serial No. 327,973

` s Claims. (ci. 1517-145) This invention relates to typewriters and thelike, and more particularly to devices therein to hold a platen removably or exchangeably in position. f

Devices for this generally are well known and in vwide use. The patent to Helmond, No. 2,172,008, dated September 5, 1939 discloses such a device. In such patent, a platen, by means of bushings on projecting shaft ends of the. platen, is removably seated in saddles that are provided on a platen supporting frame, and high-leverage, toggle-action clamps bear normally firmly down on the bushings. The stated structure very eiiiciently and firmly holds the platen turnably in position but the aesthetic qualities of the machine are adversely affected by the exposed clamp parts and the saddle provisions for the platen.

It is a main object of the invention to provide a platen hold-down clamp which normally holds the platen securely and accurately in position, and which embodies as an operating handle for said clamp a platen frame and cover that shrouds normally from view the clamping mechanism as well as the general area where the saddle for the platen is situated, the said cover being movable to release the clamp and to provide a free path for removal of the platen.

Itis also an object of the invention to provide in a constructed in accordance with the foregoing object further a feature whereby as such clamp is applied by operation of the said cover into said shrouding position, certain members of the clamping mechanism which consttute a clamp actuating toggle will become strained and will automatically snap into an'over-center position for the clamp to stay applied and further for the cover 'to bear resiliently down upon the platen frame to the end of preventing rattling thereof during operation of the typewriter.

i Still other objects and features of the invention willbe apparent upon consideration of the detailed description which follows, as the description is read in the light of the accompanying drawings.

Now specifically referring to the drawings, Figure 1 is a fractional rear perspective view lookingdown at an angle on the right end rear portion of a typewriter` carriage, the view showing a pivoted carriage end` cover constituting a platen clamp operating handle;

Figure 2 is a fractional left hand side elevation of a platen carriage or frame showing the details of the platen clamp-down device of the invention, the clamp being in a cast-olf position permitting free removal of the platen.

Finally, Figure 3 is a side elevation similar to Figure 2, but showing the platen clamp in effective position.

Now directing attention more particularly to Figure 3, the numeral identities a platen frame comprising two spaced4 upright carriage ends 11 of which only the left one is shown, such carriage ends being connected by a tie bar 13 extending between the said carriage ends.

A conventional platen roll 14 having at least one end thereof a shaft 15 rigidly extending therefrom and having at such end an axially conlined bushing 16, is seated by means of such bushing 16 n an open saddle formation 17 provided in the carriage end 11. The said bushing 16 has usual end flanges 18 flanking the lateral clamp sides of the saddle 17 and thereby locates the platen axiallyr upon the frame 10. A mechanism is provided to clamp releasably the bushing 16 tightly seated upon the saddle formation 17. This clamping mechanism comprises a clamp lever 20 pivotally Vsupported at 21 behind the saddle formation 17 on the platen frame end 11. Said clamp leverr20 has adjustably supported thereon a screw 22 having a head bearing normally with pressure upon the bushing 16. Said clamping mechanismv moreover includes as an operating element therefor a cover or shroud 23 which overlies normally the carriage end 11 n a manner toconceal the parts at the saddle 17 and certain parts of the clamping mechanism. The said cover or shroud 23 comprises a box-like structure which is open at the bottom and includes a left and a right side wall 25, both reaching down to Hank oppositely the carriage end 11. The said cover or shroud 23 is pivotally carried upon the carriage end 11 by means of a pin 26 which extends through perforations provided in the two side walls 25 of the cover and also a perforation in the rear of the carriage end 11. Pivoted also on said pin 26, to move unitarily with said cover 23, is an arm 27. The said arm 27 pivots as a unit with said cover 23 in that it is formed with a slot.28 whereby it has a hooked association with a pin 30 extending between the two side walls 25 of the cover, the said pin 30 at both ends being riveted to the cover walls 25. The said arm 27 has a pivotal connection at 32 with oneend of a link 31. the other end the said link 31 has a pivotal connection with the clamp lever 20. The said arm 27 and the link'31 constitute an operating toggle for the clamp 20. The toggle 27, 31 is operable from a folded to a straightened position to apply the clamp 20 and reversely to release thev clamp. In being applied by said toggle 27, 31, the clamp is first moved rapidly to take a position over the platen bushing 16, and then at decreasing speed but rapidly increasing leverage.

As has been stated, the toggle 27, 31 is forced past dead center position in order that the clamp 20 will stay applied. The toggle link 31 then exerts a reacting force below the center of the pivotal pin 26, thereby urging the arm 27 Valong withrthe associated cover 23 clockwise with reference to the showing of Figure 3. However, the front end of the cover 23 at 35 meets the top of the carriage end piece 11, and the toggle thereby is stopped against further movement beyond dead center position. The clamp Z0 therefore will not only stay applied firmly upon the platen bushing V16 but the cover 23 under the resilient force supplied by the gooseneck 33 will firmly seat at 35 and will not rattle during operation of the typewriter. The clamp 20 is readily releasable by grasping the front end of the cover 23 and swinging it upwardly and rearwardly to the position'illustrated in Figure 2. The cover thus .takesupaposition rearwardlyoithe. saddle. 17-.and the toggle 27, 31 moves thev clamp upwardly to a position also rearward of the saddle 17, whereby a clear path is. provided oriupward removal yof the `platen 14, it'being understood. thatianother-platen `may thus be-v substituted. The `limit of'rearwardswingingxmovementofthe cover 23 is;deterrnint-:dsby` a reainwall 36` striking a lower l edge of thef'platen frame asatl37 inL Figure 2.

The strength ofclarnping exerted bylithelscrewfZZfof the .clamp 20zis` adjustableby. turning the -screwl'ZZon the clamp; and fixing =the obtainedvl adjustment'rby drawing' up nutseSS tightly. .Preferably theladjustmentismade so thattheyield'.affordedby the gooseneckSSis almostfully recovered inftheposition of the `parts seeninfFigure3.A In order. to effect .the stated:v adjustment4 without ninterference by. ithe'cover23, the latterlmay temporarily beA removed from theiplaten frame:bywithdrawingthepin26 and'moving thevcoverftoldisassociate thepinlllfrom theslot' 23. With the pin vv26' theny `reinserted 4to -pi-votthe' arm`j27, the 'clamp'.i20 may then' be-operated and testedl by simply operating: the toggle 127, 31, appropriate adjustmentA offthe clampr screw? 22-being-made to exert the desired pressure on the vibushing 16. fTo flimit -the throweoflthe toggle" beyond'idead centerpo'sitionin the absenceof 'the covergthe toggle .link-31 is provided'with a'benbf earl40to strike the top edge-of theside piece 11. The--proper action;of the clamphhaving =beenobtained;-the -cover is then added to itheiassembly. fThe/ said--ear40 is #located so'thatifithe clampistapplied -byoperationrof the cover23,-it will'just i beashortuostriking the end-*piece 11," as Tis evident from Figure' 3,:whereinthere -is `shown a srnalln space under said ear.

'Variations may be resortedto within the scope ofthe invention.

'.'Whatis 'claimed-is:

lJThewcombinationlwith a-platen frameend piece having a\saddleffor seating aremovableplaten, ofa clamp mounted on said end piece to swing inthe general plane thereof-oppositely lto an appliedposition and to .,a. re-

leased-position respectively tohold said. platenseated invsaidfsaddle and'to free 'it for removall from said saddle, ah'toggle'operable froma'folded to'slightly' beyond a straightened condition -to apply said clamp andy hold it applied. and=reversely-operable to' release saidclanjlp,v a cover normally inlaiposition overlying .said end piece and said clamp, means mounting said cover formovement betweenrsaid overlying positionJ and a raised position, 'the coverin "the latter position allowing removal of .the platen, a-'rstopz'engageablel-bysaidcover in reaching said overlying po'sition, and 'means to' actuate'the toggle to folded condition -by'mOVement' ofthe cover from said overlyingposition to the said'raised position, and to actuilte said ltoggletofthe said slightly beyond straightened. condition by movement of the cover from saidi-raisedto said overlying position,--saidtoggle'in being operate'djbeyond said-:straightened condition' holding said: 'clamp applied and also=exerting a force on Ythe cover ldirec'tionally .to urge it resilientlyagainst said stop.

IZS'lS'hecombination with aplaten frame end having a saddlewforlfseating 'a removable platen, of a cover Anormally:in a position overlying said lplaten frame end, means mounting saidcoverior movement between said overlying and;a-raised-position,-applicable and releasable platen hold-down means comprising, a clamp mounted on said frame-end-toswingoppositely to an applied position and toa-released position, a toggleoperablefrom a folded condition-.to slightly 'beyond-a straightened condition by the movement of'said' cover` to said overlying position, therebyi toy apply said clamp and; holdV it applied, said toggle .operable to 'release said clamp by `movement of the-cover to thesaid raised position, an abutmentengageable bysaid cover lin reaching said overlying position, andy resilientl means included -in said' hold-down .means andefectivecwhennhe toggle is, in `the said slightly beyond straightened condition to keep said clamp resiliently active andat- -thesame Ytime -toexert a resilient {orcedirectionally on said cover for;it to contact said abutment.

3. The combination with a platen frame end having a saddle for seating a removable platen, of a cover normally in a position overlying said'platen frame end, means mounting said cover for vmovement'between said overlying and a raised position, a clamp mounted on said frame end` to swingoppositely to an applied position' and 'to a released position, a toggle comprised of two members,.op erable from a Vfolded condition to slightly beyond a straightened conditionby the movementofsaidcover to said overlying position, thereby to apply said clamp and hold it applied, said toggle operable tol release said clamp by movement of the cover tothe said raisedposition, and an abntmenton said frameengageableby saidcover. in reaching said overlying position, one member of saidtoggle being flexible in length and effectivel when thetoggle is in 'the' saidslightly beyond straightened condition-to keep said clamp resiliently active and at the, same. timeeffective to exert a resilient'forcedirectionally on. saidcover for itto contact `said abutment.

'4.The combination with a platen frame end piece havinga-'saddlefor seating aremovable platen, ofa clamp pivota'lly mounted on said end, piecefcloselybehind'said saddle; to swing" from b'ehind said saddleforwardlyI and downwardly to a platen hold-down position over the saddle,'and to swing oppositely toa released position behind said saddle to'free said platen for upward removal from said saddle, a` toggle linked to. said clamp and -by operation to a straightened condition swinging said clamp to said holddown position and by. operation to an upwardly broken Vcondition swinging said clamp to said'released position,- a cover ynormallyoverlying and concealing: said .end piece, thesaid saddle and the said toggle, meanspivot'ally mounting said cover on .said end piece near its rear extremity to swing .upwardly and rearwardly from its overlying position to a raised positionclear to the rear of Asaid saddle, and. means, associating said cover operatively with said toggle so. that movement of the coverdownwardly from said raised to said'overlyingposition .will straighten the .toggle and apply'the. clamp, and so that movement of thevcover from said-overlyingv to said raised position will break the toggle upwardly and will release the clamp, thereby rendering 'the platen freely removable.

l5.'T.he combination with a platen frame end. piece having'a saddle'forseating a .removableplatem .of a clamp pivotally mounted on s'aid end piece closely behindsaid saddle, to swing from behind..saidsaddleforwardly and downwardly vto a platen hold-down position over the saddle,.and to swing oppositely to a, released position behind said saddle to'free said platen for .upward removal from said saddle,Y a cover normally overlyingand concealing 'the said endl piece, .the said saddle andthesaidclamp, axis means near the, reanextrernity ofthe .cover-mounting the latter toV swingupwardly vand rearwardly from its overlying position .toa raisedy position clear tothe rear of the-saddle, andmeansto actuatesaidclamp oppositely' between `said two ,positions by'oppositely swinging said coverbetween said overlying and said raised position, comprising, a link ,haying .at one enda pivotal connection with said clamp and having at the'otherend another pivotal connection in a constant relationA to said cover, the said other ypivotalconnection whenr'the cover is in. said overlying position being disposed substantially on a straight line intermediate said cover-axis `and ythe first said pivotal connection, and swinging upwardly and-rearwardly with 'the cover to release ythe clamp.

ReferencesCitedin the'fle of thisrpatent 'UNITED STATESPATENTS 

